Abstract
Fully self-consistent ab initio electronic structure calculation of the theoretical tensile strength of single-crystalline copper and NiAl loaded uniaxially along several crystallographic directions is performed using the full-potential LAPW method. In copper, the calculated theoretical tensile strengths are about an order of magnitude higher than the measured ones. This is in contrast with a recent similar analysis performed for tungsten where a good agreement with experimental data was attained. This indicates that another instability occurs in the material before the critical tensile stress is reached. In NiAl, the "hard" orientation [001] differs very significantly from the [111] orientation; this anisotropy may be understood in terms of higher-symmetry structures present along some deformation paths.

Key words
copper, NiAl, tensile strength, full-potential LAPW method, higher-symmetry structures

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